Closed cleansing system

ABSTRACT

A closed cleansing system for degreasing purposes. The cleaning chamber is also used as a solvent still, and the solvent is circulated through the system in a closed circuit to achieve improved results. Disposal of oil and dirt from the system may be accomplished by means of removable absorbent granules and pads or by a drain system. In one form of the invention the solvent is condensed in the bottom of the cleaning chamber and sealed therefrom by a sliding aperture plate acting as a valve to facilitate chamber access.

United States Patent 1 lnvenwr Joseph Pompei 1.1 15,198 10 1914 Hirsch68/18 1420 South Ridgeland y 1,291,266 1 1919 Traube 1. 68/18 x 604021,338,308 4/1920 Krouse i. 68/l8 X 1 1 pp 774,601 2,004,375 6/1935Martin 68/18 x [22] Filed June 14, I968 K45] Palcmed July 27 197]Primary Exammer-W1ll1am l. Prlce An0rneyParker and Carter [54] EYSTEMABSTRACT: A closed clean sing system for degreasing purposes. Thecleanmg chamber is also used as a solvent st1ll, and U.S. the olvent iscirculated through the System in a closed circuit Cl 43/08 to achieveimproved results. Disposal of oil and dirt from the of Search t systemmay be accomplished means of removable absor. bent ranules and ads or ba drain 5 stem. In one form of the {56] References inven tion the solvnt is coni iensed in ihe bottom of the clean- UNITED STATES PATENTS ingchamber and sealed therefrom by a sliding aperture plate 434.84] 8/1890Schuessler 68/ l 8 acting as a valve to facilitate chamber access.

PATENTED JUL27 I97! m Fr @M .NN

. mwv

CLOSED CLEANSING SYSTEM SUMMARY OF THE INVENTION The present inventionrelates to a closed cleansing system and more particularly to acleansing system employing a volatile solvent for degreasing metal partsof similarly cleansing articles of plastic, fabric, and other materials,as for example dry cleaning clothing.

Conventional systems for degreasing metal parts and for cleaningclothing commonly utilize a hydrocarbon halide solvent such asperchlorethylene or trichlorethylene. These systems have seriousdisadvantages in that, although the solvents can be reused, thepotential economy and convenience are largely unrealized because most ofthe solvent is lost by evaporation, contamination, and trapping. Also,the conventional open systems are unsafesince the solvent is toxic andmay be flammable, thus creating danger to the operators and to property.Exhaust systems for degreasing machines employing such solvents do notcompletely eliminate all the dangerous fumes, and also tend to draw offand discharge much of the solvent, 'thus wasting solvent andcontributing to unhealthful air pollution. Even whcn an absorbent suchas activated carbon is employed in the exhaust system, almost all of thesolvent is lost Recovery of solvent from the absorbent is relativelycomplicated and expensive while requiring the use of bulky equipment.Additionally, the solvent may break down to form poisonous and corrosivebyproducts such as hydrochloric acid and phosgene gas as aresult ofexposure to strong direct light, overheating, reactions of contaminatedsolvent, moisture, and other causes. This may result in rusting of theapparatus or of the very parts being cleaned.

The foregoing drawbacks arise primarily from the extensive use ofequipment which leaves the solvent exposed to the atmosphere. Suchequipment may comprise an open tank containing the parts to be cleanedby the solvent, with a cold water jacket surrounding the tank just belowthe open top for condensing the vapor. A tank large enough foraccommodating an economical quantity of parts has an opening too largeto sufflciently condense all of the solvent so that a large proportionof the solvent is unavoidably lost. Open equipment also exposes thesolvent to light and moisture and increases the danger of contamination.Moreover, in prior batch-type degreasing equipment, whether open orclosed, the solvent vapor acts first on the lower parts, which arecleaned and brought to substantially the vapor temperature. The upperparts of the work are cleaned later by the rising vapor so that oil anddirt may run down and cause streaking and resoiling of break downpreviously cleaned work. To avoid this, the equipment is loaded to onlya small fraction of its rated capacity to allow all of the work to beacted on substantially at one time. This is wasteful, inefficient, andgreatly slows production. Closed apparatus previously proposed have notbeen adopted to any appreciable extent as a result of their complicatedand expensive design, slow operation, and lack of advantages over openequipment. Prior machines also require periodic interruption ofoperation for cleaning.

The closed system of this invention provides numerous advantages overthe prior devices. The invention provides an apparatus capable ofcyclical operation in which the solvent is vaporized in a closed chamberused for cleaning the work, with the solvent being removed from thechamber and condensed in a closed solvent tank. The solvent is moved ina circuit between the chamber and tank by means of a piping systemincorporating a single pump. The piping system may be operated toprovide low and high pressures in one or the other of the tank andchamber as desired. Chamber pressure may be varied from a low pressureto facilitate vaporization at low temperature or to a high pressure toallow solvent superheating. The different pressures possible in thesystem provide flexibility for operating under varying circumstances,The available pressures permit substantially complete vaporization toavoid loss of solvents which may be trapped in holes or crevices of thework, or in fabrics or other absorbent materials. The completevaporization also results in cleaning all of the work at substantiallythe same time and rate to eliminate resoiling of work already cleaned. i

With the closed system of this invention solvent is not lost byevaporation and is safeguarded against contamination and deteriorationso that a relatively small quantity of solvent is required. Theinvention provides a. system economical to install and operate in thatno exhaust system is required, and the system is safe even though toxicor flammable solvents are utilized. 9

The invention also provides a cleansing system which is much easier toclean and maintain. Since the solvent is removed from the cleaningchamber in its vapor phase the oil, grease or dirt which is removed isleft at the bottom of the chamber where it may be removed by draining orby remova ble absorbent pads or granules. This may be accomplished aseach batch of work is removed. Thus, costly down time for periodiccleaning is avoided.

Accordingly, it is an object of this invention to provide a safe,efficient, versatile, and economical system for cleansing articles ofmetal, plastic, fabric, and other materials, using a volatile degreasingsolvent. i

Another object is to provide a cleansing system of the type describedusing a small quantity of solvent in such a manner as to conserve thesolvent and maintain it against contamination and detcriorization.

Another object is to provide a closed cleansing system which avoidscontamination of the surrounding atmosphere with solvent vapor withoutthe need for an exhaust arrangement. 7

Another object is to provide a cleansing system which excludes light andmoisture to avoid corrosion of the work and equipment.

Another important object is to provide a cleansing system which may beeasily cleaned without interrupting the cycle of operation.

Another object is to provide a cleansing system which removes allsolvent from the work regardless of its configuration or absorbency. i

Another object is to provide a closed cleansing system that may safelyemploy toxic or flammable solvents.

Another object is to provide a cleansing system which effectively andeasily operates at varying temperatures and solvent pressures toaccommodate varying work materials.

Another important object is to provide a cleansing system in which allparts of the work are cleaned substantially simultaneously to avoidresoiling of the work.

Another object is to provide a cleansing system having a solventcondensing chamber communicating with the cleansing chamber by means ofan apertured plate acting as a valve.

Yet another object is to provide a cleansing system which may be readilycleaned by providing removable absorbent pads or granules in the chamberadapted to hold dirt and other particles removed from the work.

Other objects and advantages of the invention will become apparent tothose skilled in the art when the followingspecifi cation is read inconjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. I is a partially diagrammaticillustration of a cleansing system incorporating features of theinvention;

FIG. 2 is a fragmentary sectional view of a cleansing systemincorporating means for shutting off a quantity of solventv in thebottom of the chamber; and 1 F IG. 3 is a view similar to FIG. 2illustrating a modified form of the invention.

DETAILED DESCRIPTION Referring now to the drawings and particularly FIG.1 a preferred embodiment of the cleansing system of the invention isillustrated as incorporating a cleaning chamber indicated generally at10. The chamber is heated by means of stcam in steam jacket 11 passingthrough inlet 12 and outlet 13. The chamber is closed except for anaccess opening 14 through which the work to be degreased or cleaned isinserted and removed. Opening 14 is closed by a suitable door 15provided with a sight glass or window 16. A drainpipe l7 and valve 18are provided at the bottom of the chamber for drain ing off oil, grease,and other soil removed from the work.

The chamber may be easily cleaned by providing a removable layer ofabsorbent material 19 on the bottom. This niaterial may be in the formof a mat or pad, or in granular or pul verulent form. FIG. 3 illustratesone manner of utilizing a layer ofabsorbent material 19.

Chamber 10 also functions as a cooling device when water or other fluidis passed through the jacket. Thermometer 20 and pressure gauge 21communicate with the interior of the chamber to indicate temperature andpressure conditions.

The circuit means for the solvent includes the cleaning chamber 10, asolvent condenser 30, a solvent receiving tank 25, a pump 35, and apiping circuit combining the elements in a novel manner. Liquid solventfrom tank is directed to the chamber by means of conduit 22 controlledby shutoff valve 23. A drain valve 24 and bleeder valve 29 are connectedto conduit 22. Bleeder valve 29 may be selectively operated to equalizethe pressure inside and outside chamber 10. Tank 25 is provided withsight window 26, thermometer 27, and pressure gauge 28 to monitorconditions inside the tank.

Solvent condenser 30 may be of conventional construction incorporating asolvent passage, not shown, connected at one end to tank 25 and at itsother end to chamber 10 by conduit 31 under control of shutoff valve 32,Condenser 30 may be cooled by suitable cooling water or fluidcirculating through inlet 33 and outlet 34.

Pump 35 moves the solvent to and from the chamber by effecting partialevacuation of either the chamber or sol vent tank. Conduit 36 andcontrol valve 37 interconnect the chamber with the suction side of pump35 while conduit 38 and control valve 39 connect the suction side withtank 25. Alternatively, the valves 37 and 39 may be replaced by aconventional three-way valve operable for selectively connecting thepump to the chamber or tank and for shutting off both chamber and tankfrom the pump. The exhaust side of the pump is directed through conduit40 under control of valve 41. A bypass conduit 42 controlled by valve 43interconnects the exhaust side with conduit 38 and tank 25.

In operation the work to be cleaned is placed in the chamber on asuitable support, such as plate 63 of FIG. 3. Door 15 is closed and thechamber is heated by means of steam jacket 11. All valves of the circuitare closed except valves 37 and 41, and pump 35 is operated to partiallyevacuate the chamber. After chamber pressure has been reduced to apredetermined level, valve 37 is closed and valve 23 opened so thatsolvent is drawn by the pressure differential from tank 25 into thechamber. To increase the speed and force of solvent injection, exhaustvalve 41 may be closed and bypass valve 43 opened so that air from thechamber is pumped into the tank to increase its pressure. Otherwise,valve 41 remains open and valve 43 closed throughout the operation.Injection conduit 22 may have a nozzle arrangement, not shown, withinthe chamber to direct the solvent in a plurality ofjets against the workto dislodge insoluble particles or other accumulated material. Withclothing or other fabric articles, a spray arrangement assures that thework is subjected to the liquid solvent for proper cleaning.

Valve 23 is then closed to stop the flow of solvent into the chamberwhile a quantity of solvent still remains in the tank. Valve 39 isopened so that the pump draws air from tank 25 to reduce the pressurewithin both it and condenser 30. During this time the solvent in thechamber is heated under a reduced pressure to effect substantiallycomplete vaporization, starting from the initial relatively low solventtemperature. The solvent vapor acts upon the work to dissolve oil,grease and other dirt or soil, which then drops to the bottom of thechamber.

Streaking or rcsoiling of the work is avoided because all of the work isacted upon substantially simultaneously by the vapor. This occurs whenthe initially light vapor builds up in density and temperature uniformlythroughout the chamber to condense substantially at the same rate on thework. Work which is metal or the like is maintained throughout theoperation at a lower temperature than the vaporized solvent becausetransfer of heat to the work is by the solvent vapor, the temperature ofwhich constantly increases by contact with the chamber walls whilesolvent pressure increases due to continued generation of vapor. Workwhich is fabric or the like is cleaned by contact with liquid solvent,which is vaporized after removal of the dirt. The fabric issubstantially at the vaporization temperature of the solvent so that nocondensation occurs.

As solvent heating and vaporization continue, the chamber pressureincreases until it reaches a predetermined value, such as atmosphericpressure, as indicated by gauge 21. At this point all valves exceptvalves 32, 39, and 41 are closed so that the partial evacuation of tank25 causes solvent vapor in the chamber to pass into condenser 30 whereit is condensed and delivered into tank 25. Valve 39 is then closed andpump 35 stopped while bleeder valve 29 is opened to allow the pressurein chamber 10, tank 25, and condenser 30 to equalize outside pressure.At this time door 15 may be opened to remove the clean work. Oil orother liquid material removed from the work may be drained from thechamber by opening valve 18. Other collected dirt may be removed throughopening 14. Where the absorbent layer 19 is employed it may also beremoved along with the accumulated dirt or soil and then replaced. Thecleansing apparatus is now ready for another cycle. If desired, thepressures in the tank, condenser and chamber may be equalized afterreturn of solvent to the tank by opening valve 43 to providecommunication through valve 41 to the exterior ofthe tank.

The valves have been illustrated as manually operated, but it isunderstood that they may be automatically operated. Programming of thecycle of operations may be employed so that pressures and temperaturesare automatically matched to the particular cleaning problem so that thebest results are 0btained with the work material involved and the typeof soil or dirt to be removed. Thus, higher temperatures and pressuresmay be required to effect superheating of the solvent vapor to removegreases having relatively high melting points. On the other hand,certain materials which cannot withstand elevated temperatures mayrequire a relatively low temperature with an increased period of solventexposure. Also, various solvent types may be employed, a typical exampleof which is a chloronated hydrocarbon having a bowing point in thevicinity of240 F. at one atmosphere,

FIG. 2 illustrates a modified form of the invention in which thecleaning cycle may be varied so that during work loading or unloadingsolvent remains in the bottom of the cleaning chamber. As a result theoperator is not exposed to the solvent and the solvent does not escapeor become exposed to contamination. During such a cycle it may bedesired to shut off the tank and condenser from the cleaning chamber bythe valving arrangement.

The cleaning chamber 50 of the embodiment of FIG. 2 is generally similarto the chamber of P10. 1. Opening 14 and door 15 provide access to thechamber while drain pipe 17 and valve 18 control removal of liquid oiland grease. A boil ing sump 52 is connected to the bottom of chamber 50by means of control valve 53 and conduit 51. Outlet 54 and valve 55 areprovided to drain the sump.

During the cleaning cycle valve 53 is opened and sump 52 heated by thechamber heating means, not shown, so that the solvent is vaporized anddriven into the chamber for cleaning the work. To remove the cleanedwork, heating is discontinued and the solvent condensed so that itcollects in the sump. Valve 53 is then closed to trap the solvent andisolate it from the chamber so that the door may be opened for removalof the work with complete safety. Valve 53 may be mechanically closed asthe door is opened through a suitable linkage, not shown.

Referring to HO. 3 another modified cleaning chamber of the inventionillustrated generally as 60. Chamber 60 is provided with an opening 14and door 15, as well as oil drain pipe 17 and valve 18. An absorbentmaterial 19 is provided on the bottom of the chamber to collect dirt andother particles removed from the work. Absorbent material 19 may be aonepiece sectional pad or mat, and may comprise a layerofgranular orpulverulent material.

An apertured work support plate 61 disposed within chamber 60 on anglemember 62 separates the chamber into upper and lower sections. A secondapertured valve plate 63 is slideably positioned on support plate 61.Alternatively, the valve plate may be disposed below plate 61, which inturn supports the work. In the position illustrated the apertures of thetwo plates are in registry so that vapor may readily pass between thechamber sections. Valve plate 63 may be manually moved by handle 64 sothat the apertures are out of registry to close communication betweenthe two sections. Suitable means may be provided for opening and closingthe valve plate automatically as door is respectively closed and opened.

in operation, work to be cleaned is first placed on valve plate 63. Withvalve plate 63 in its open position the solvent in the lower section isheated and vaporized to move into the upper chamber for cleaning.Following the cleaning, the heating is stopped and the vapor condensedso that it collects in the lower section. The valve plate is shifted toits closed posi tion to trap the solvent below the plates so that door15 may be opened without escape of solvent.

it will be understood that various changes in the details andarrangement of parts, which have been described and illus- I trated inorder to explain the nature of the invention, may be made by thoseskilled in the an within the principle and scope of the invention asexpressed in the appended claims.

lclaim:

1. Apparatus for cleansing work articles with solvent comprising thecombination of:

a cleansing chamber having a first section for receiving the workarticles and a second section for receiving liquid solvent;

means to distill the solvent in the second section for dischargingsolvent vapor into the first section;

means to condense the solvent after the work articles are cleanedwhereby liquid solvent is delivered to the second section;

valve means operable in a first position to provide open communicationbetween the first and second sections during solvent distillation and.condensation, and in a second position to close said communication andtrap solvents in the second section to permit safe removal of the workarticles from the chamber.

2. The invention ofclaim l and further characterized in that the valvemeans includes an apertured work support plate between the first andsecond sections, and an aperture valve plate in sliding relationshipwith the work support, said corresponding apertures of the support andvalve plate being in registry in said first valve position and being outof registry in said second valve position.

3. The invention ofclaim l and further characterized in that said secondsection comprises a sump for receiving the solvent, said sump beingpositioned below said chamber, and wherein said valve means comprises aconduit interconnecting said sump and bottom of said chamber and a valvein said conduit selectively operable between opened and closedpositions.

4. The invention of claim 1 and further including an absorbent padremovably positioned in the bottom of said chamber for receiving thematerial cleaned from the work.

5. An apparatus for cleansing work articles with solvent, said apparatuscomprising the combination of:

a cleansing and vaporizing chamber;

a solvent receiving tank;

a solvent condenser communicating with the chamber and the tank; andcircult means to create a pressure dlfferential between the chamber andthe tank for drawing liquid solvent into the chamber for cleaning thearticles, and to create a pressure differential between the tank and thechamber to draw evaporated solvent through the condenser into the tankafter cleaning of the articles, said circuit means further includingbypass means to selectively connect a pump means with the tank topressurize the tank, thereby forcing the solvent into the chamber.

6. The invention of claim 5 further characterized in that removal ofmaterial removed from the articles is facilitated by removing anabsorbent pad removably positioned in the bottom of the chamber.

7. The invention of claim 5 further characterized in that removal ofsolid material cleaned from the articles is facilitated by removing anabsorbent pad removably positioned in the bottom of the chamber and adrain in the bottom of the chamber to selectively drain liquid materialcleaned from the articles.

1. Apparatus for cleansing work articles with solvent comprising thecombination of: a cleansing chamber having a first section for receivingthe work articles and a second section for receiving liquid solvent;means to distill the solvent in the second section for dischargingsolvent vapor into the first section; means to condense the solventafter the work articles are cleaned whereby liquid solvent is deliveredto the second section; valve means operable in a first position toprovide open communication between the first and second sections duringsolvent Distillation and condensation, and in a second position to closesaid communication and trap solvents in the second section to permitsafe removal of the work articles from the chamber.
 2. The invention ofclaim 1 and further characterized in that the valve means includes anapertured work support plate between the first and second sections, andan aperture valve plate in sliding relationship with the work support,said corresponding apertures of the support and valve plate being inregistry in said first valve position and being out of registry in saidsecond valve position.
 3. The invention of claim 1 and furthercharacterized in that said second section comprises a sump for receivingthe solvent, said sump being positioned below said chamber, and whereinsaid valve means comprises a conduit interconnecting said sump andbottom of said chamber and a valve in said conduit selectively operablebetween opened and closed positions.
 4. The invention of claim 1 andfurther including an absorbent pad removably positioned in the bottom ofsaid chamber for receiving the material cleaned from the work.
 5. Anapparatus for cleansing work articles with solvent, said apparatuscomprising the combination of: a cleansing and vaporizing chamber; asolvent receiving tank; a solvent condenser communicating with thechamber and the tank; and circuit means to create a pressuredifferential between the chamber and the tank for drawing liquid solventinto the chamber for cleaning the articles, and to create a pressuredifferential between the tank and the chamber to draw evaporated solventthrough the condenser into the tank after cleaning of the articles, saidcircuit means further including bypass means to selectively connect apump means with the tank to pressurize the tank, thereby forcing thesolvent into the chamber.
 6. The invention of claim 5 furthercharacterized in that removal of material removed from the articles isfacilitated by removing an absorbent pad removably positioned in thebottom of the chamber.
 7. The invention of claim 5 further characterizedin that removal of solid material cleaned from the articles isfacilitated by removing an absorbent pad removably positioned in thebottom of the chamber and a drain in the bottom of the chamber toselectively drain liquid material cleaned from the articles.